Slim Handheld Controller with Passive Optical Markers for 6DOF Tracking

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Solution Overview

Problem

Existing wireless hand-held controllers for mixed reality systems lack accurate 6DOF tracking, requiring high processing overhead and struggling with precise location and orientation detection, especially in virtual and augmented reality environments.

Innovation Solution

A wireless hand-held inertial controller with passive optical and inertial tracking in a slim form-factor, featuring optically reflective markers and an IMU, which combines optical position tracking with inertial orientation data to provide accurate 6DOF tracking with reduced processing overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If passive optical tracking with reflective markers is used, then measurement precision of controller position is improved, but device complexity increases due to additional markers and optical components

Engineering Contradiction:

Improvecontroller position detection accuracyVSAvoidcontroller structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses optical reflective markers that create optical copies/reflections detectable by the depth camera, allowing position tracking without active emission from the controller. The markers reflect ambient or structured light back to the camera, providing position information through optical copying rather than requiring complex active illumination systems.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent replaces complex mechanical or active electronic tracking systems with a passive optical system. Instead of using active transmitters, receivers, or complex mechanical encoders on the controller, the solution uses simple reflective markers detected by optical sensors, substituting mechanical complexity with optical field interactions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If inertial measurement unit (IMU) is integrated into the controller, then orientation tracking accuracy is improved, but weight of the controller increases

Engineering Contradiction:

Improveorientation tracking accuracyVSAvoidcontroller weight

Core Design Contradiction:

Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent combines optical position tracking with inertial orientation tracking in a unified 6DOF system. The IMU data (accelerometer and gyroscope) is fused with optical marker position data from the depth camera, merging two tracking modalities into a single integrated controller system that provides both position and orientation information.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the measurement parameters by using passive reflective markers instead of active transmitters, and by fusing inertial parameters (acceleration, angular velocity) with optical parameters (marker position). This parameter fusion allows accurate 6DOF tracking while keeping the controller form-factor manageable through efficient sensor integration.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If 6DOF tracking is implemented, then productivity of interaction is improved, but use of energy increases due to continuous position and orientation monitoring

Engineering Contradiction:

Improveinteraction efficiencyVSAvoidcontroller energy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic tracking updates where the depth camera captures marker positions at discrete time intervals rather than continuous monitoring. The IMU provides continuous orientation data between optical updates, creating a periodic fusion schedule that maintains 6DOF tracking accuracy while reducing overall computational and energy demands compared to truly continuous monitoring.

Inventive Principle:

Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables precise and accurate 6DOF tracking of the hand-held controller with reduced computational requirements, enhancing interaction in VR and AR environments by using a stylus form-factor with two IR markers and an IMU for improved detection and orientation resolution.

Implementation Method 1

the inertial measurement unit tracking orientation of the hand-held controller in three dimensional space relative to a predetermined frame of reference and providing orientation and acceleration data

Methodology Applied

Scientific EffectGravitation: Gravitation

Implementation Method 2

a first optically reflective marker at or proximate the first end and a second optically reflective marker at or proximate the second end; an optical sensor located on the display for determining the position of each of the first and second optically reflective markers

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS10521026B2Passive optical and inertial tracking in slim form-factor

Publication Date: 2019.12.31 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

Systems are provided that include a wireless hand-held inertial controller with passive optical and inertial tracking in a slim form-factor. These systems are configured for use with a head mounted virtual or augmented reality display device (HMD) that operates with six degrees of freedom by fusing (i) data related to the position of the controller derived from a forward-facing optical sensor located in the HMD with (ii) data relating to the orientation of the controller derived from an inertial measurement unit located in the controller.